The present invention relates to an auto-index method intended for electronic publications, i.e., general document files as contents and a method of utilizing the same.
In general prior art, when words and phrases that become candidates for an index are included in the text of electronic publications, a compiling operator designates words and phrases of respective index candidates to thereby compile an index. As a method of compiling an index by designating words and phrases of index candidates, there are two ways for example, as follows.
A first indexing method includes compiling an index, when words and phrases of respective index candidates are registered in an index candidate dictionary, by extracting index locations at the same time. A second indexing method includes compiling an index by retrieving a word in the dictionary again and extracting the location of the retrieved and obtained word.
One of the indexing methods of this type has been disclosed in JP-A-62-154025 for instance. In this prior art, is indicated whether the word is to be registered in an index or not, when Japanese characters "hirakana" are converted into a word or phrase combined with Chinese characters "kanji" at time of composing a document or sentence. This is an operation peculiar to a Japanese word processor. In the case of an English word processor for instance, this operation corresponds to a technique of inputting several words and performing conversion to replace these words with other words.
In this prior art, however, since indication of index registration is performed by a user operation, the workload of an index compiler (User) becomes heavy when the number of registration words is large.
Further, JP-A-61-75952 discloses a technique for retrieving a required document file from a plurality of document files using keywords extracted from the respective document files. Those words that are inputted frequently are selected and extracted while sentences are being inputted. Then, the extracted word and a similar word thereof are made into a set, which is handled as a keyword and stored in the file. According to this method, all of the extracted words and phrases are related to documents as keywords and stored in the file. In this prior art, however, the words and phrases to which an index is actually compiled are not selected.
As described above, a method appropriate for compiling an index has not been known in either technique. There has been such a problem that an efficient method requires a heavy workload. Further, although indexing of electronic document files has been made in the prior art, no consideration has been given to a method of outputting documents using the indexing, i.e., a method of utilizing a compiled index.